Currently, use of optical scopes on firearms is hampered by several major disadvantages. First, optical scopes are vulnerable to glare caused by direct sunlight hitting the light gathering lens of the scope. Second, the field of view seen through a scope is subject to distortion caused by heat rising from the gun barrel. Lastly, inadvertent displacement of the eye of a viewer results in a parallax displacement of objects seen through the scope. Additionally, most scopes make no provision for the attachment of additional optical filters or polarizers.
Although devices have been developed which shade optical scopes from glare, such as U.S. Pat. No. 4,089,117 to Villarreal and U.S. Pat. No. 4,926,560 to Kilgore et al, no devices exist which address the problems of heat distortion and parallax shift. Thus, there exists a further need for a device which will not only prevent glare but will also eliminate the problems of heat distortion and parallax shift and allow for the attachment of filters and polarizers.